Operator 'In' into TList<>

[Max Max]

why during the cycles of interactions on tlist with the 'in' operator item free memory?

type
  stack = class(TStack<Integer>)

  end;

procedure TForm1.btn1Click(Sender: TObject);
var
  Lista : TList<stack> ;
  var item : stack;
begin

    lista := TList<stack>.Create;
    item := stack.Create;

    item.Push(2);
    Lista.Add(item);


    for var x in lista do
        ShowMessage('interatore') ;

    for var x in lista do             // <<------ item not exist, in more case generate Exception
        ShowMessage('interatore') ;
end;

Thank you.

[Stefan Glienke]

Because Spring collections are not meant to be used as objects but as interfaces. Use IStack and create via the factory method from TCollections.